1.什么是spring
spring 是分层的JavaSE/EE轻量级应用开源框架,已控制反转IOC和面向切面编程AOP为核心,提供了展现层SpringMVC,
和持久层Srping JDBC以及事务管理等。
spring是一个开源框架,为了解决企业应用开发的复杂性而创建的,但现在不止应用于企业应用。
同时是一个轻量级的控制反转ioc和面向切面编程的容器框架
轻量:从大小与开销对于spring都是轻量的
通过控制反转ioc的技术达到松耦合
提供面向切面编程的丰富支持,允许通过分离应用的业务逻辑与系统服务进行内聚性的开发
包含并管理应用对象的配置和生命周期,这个意义是容器
将简单的组件配置组合成复杂的应用,这个意义是框架
框架:框架就是定制一套规范或者规则(思想),大家在该规范或思想下进行工作,或者说
使用别人打好的舞台,你来做表演
框架于类库的区别
框架一般是封装了逻辑的,高内聚的,类库则是松散的工具集合
框架一般似乎专注于某一领域,类库则是更通用的
spring带来了复杂的JavaEE的春天
2.特点
方便解耦,简化开发
spring提供ioc容器,可以将对象之间的依赖关系交给spring控制,避免硬编码所造成的过度程序耦合。
AOP编程支持
通过spring提供的aop功能,用户可以轻松的进行面向切面编程
声明事务的支持
用户可以通过spring来管理事务,提升开发效率
方便程序的测试
可以使用非容器的依赖的编程方式进行几乎所有的测试工作,在spring中,测试不再是
昂贵的操作,而是随手可做的事
方便集成各种优秀的框架
spring不排斥各种优秀的框架,相反spring可以降低各种框架的使用难度。如可以集成(struts、Hibernate)
降低JavaEE API的使用难度
如JDBC、JavaMail、远程调用等
spring源码设计精妙、结构清晰,研究源码可以快速提升Java技术水平和开发应用水平
3.案例中使用的jar
4.直入主题IOC
4.1小案例
将对象的依赖交给配置文件来配置(配置文件的名字是可以任意的,不过一般写一个比较规范的名字),这里使用IOC特性对类中的属性进行初始化
使用junit来进行测试单元测试(注意:单元测试一些老的版本可能会存在bug,如calssNotFound...,建议下载新的junit版本)
User.java 用户bean类
- package com.xxx.spring.ioc.bean;
-
- import java.io.Serializable;
-
- public class User implements Serializable {
- private static final long serialVersionUID = 1L;
- private int id;
- private String name;
- private int age;
- private String gender;
-
- public User() {}
-
- public User(int id, String name, int age, String gender) {
- super();
- this.id = id;
- this.name = name;
- this.age = age;
- this.gender = gender;
- }
-
- public int getId() {
- return id;
- }
-
- public void setId(int id) {
- this.id = id;
- }
-
- public String getName() {
- return name;
- }
-
- public void setName(String name) {
- this.name = name;
- }
-
- public int getAge() {
- return age;
- }
-
- public void setAge(int age) {
- this.age = age;
- }
-
- public String getGender() {
- return gender;
- }
-
- public void setGender(String gender) {
- this.gender = gender;
- }
-
- @Override
- public String toString() {
- return "User [id=" + id + ", name=" + name + ", age=" + age
- + ", gender=" + gender + "]";
- }
-
- }
package com.xxx.spring.ioc.bean;
import java.io.Serializable;
public class User implements Serializable {
private static final long serialVersionUID = 1L;
private int id; //用户编号
private String name; //用户名
private int age; //用户年龄
private String gender; //用户性别
public User() {}
public User(int id, String name, int age, String gender) {
super();
this.id = id;
this.name = name;
this.age = age;
this.gender = gender;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
@Override
public String toString() {
return "User [id=" + id + ", name=" + name + ", age=" + age
+ ", gender=" + gender + "]";
}
}
Spring中bean的配置:
这里说的Spring中的Bean概念,跟我们写JavaBean类不是一个概念,Spring中所有配置在xml中或使用spring来初始化的都叫Bean(dao,service,javaBean,Controller...)
IOC控制反转,控制权的转移,应用程序本身不负责依赖对象的创建和维护,而是有外部容器的创建和维护
(就像我们需要房子,不是自己去画图纸,建房子而是去请开发商去做,或房屋中介住房)
什么被反转了呢——————》获的对象的过程被反转了,依赖注入
set.xml配置文件初始化User.java中的相关属性,可以使用junit对其进行单元测试
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
-
- <bean name="user,user2" class="com.xxx.spring.ioc.bean.User">
- <property name="id" value="1"/>
- <property name="name" value="tom"/>
- <property name="age" value="20"/>
- <property name="gender" value="male"/>
- </bean>
-
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<!-- name中的user可以取别名 scope="prototype" 或singleton="false"可以设置为非单例模式 -->
<bean name="user,user2" class="com.xxx.spring.ioc.bean.User">
<property name="id" value="1"/>
<property name="name" value="tom"/>
<property name="age" value="20"/>
<property name="gender" value="male"/>
</bean>
</beans>
测试:
- import org.junit.AfterClass;
- import org.junit.BeforeClass;
- import org.junit.Test;
- import org.springframework.beans.factory.BeanFactory;
- import org.springframework.beans.factory.xml.XmlBeanFactory;
- import org.springframework.context.ApplicationContext;
- import org.springframework.context.support.ClassPathXmlApplicationContext;
- import org.springframework.context.support.FileSystemXmlApplicationContext;
- import org.springframework.core.io.ClassPathResource;
-
- import com.briup.spring.aop.bean.AwareTest;
- import com.briup.spring.ioc.UserService;
- import com.briup.spring.ioc.bean.Car;
- import com.briup.spring.ioc.bean.Coll;
- import com.briup.spring.ioc.bean.Life;
- import com.briup.spring.ioc.bean.Student;
- import com.briup.spring.ioc.bean.Teacher;
- import com.briup.spring.ioc.bean.User;
-
-
- public class SpringTest {
-
- @BeforeClass
- public static void setUpBeforeClass() throws Exception {
- System.out.println("BeforeClass 标注的方法 会最先先被执行");
- }
-
- @AfterClass
- public static void tearDownAfterClass() throws Exception {
- System.out.println("AfterClass 标注的方法 会最后执行");
- }
-
- @Test
- public void test() {
- System.out.println("test");
-
- BeanFactory factory = new ClassPathXmlApplicationContext("com/xx/spring/chap1/ioc.xml");
- UserService service = (UserService) factory.getBean("service");
- service.getUserDao().save();
- }
- @Test
- public void test2() {
- BeanFactory factory = new ClassPathXmlApplicationContext("com/xxx/spring/chap1/set.xml");
-
-
-
-
- System.out.println(factory.getType("user"));
- User user = (User) factory.getBean("user");
- User user2 = (User) factory.getBean("user");
- System.out.println(user == user2);
- System.out.println(factory.isPrototype("user"));
- System.out.println(factory.isSingleton("user"));
-
- System.out.println(factory.isTypeMatch("user", User.class));
-
- String[] str = factory.getAliases("user");
- for(int i=0;i<str.length;i++){
- System.out.println(str[i]);
- }
- }
- }
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;
import org.springframework.core.io.ClassPathResource;
import com.briup.spring.aop.bean.AwareTest;
import com.briup.spring.ioc.UserService;
import com.briup.spring.ioc.bean.Car;
import com.briup.spring.ioc.bean.Coll;
import com.briup.spring.ioc.bean.Life;
import com.briup.spring.ioc.bean.Student;
import com.briup.spring.ioc.bean.Teacher;
import com.briup.spring.ioc.bean.User;
public class SpringTest {
@BeforeClass
public static void setUpBeforeClass() throws Exception {
System.out.println("BeforeClass 标注的方法 会最先先被执行");
}
@AfterClass
public static void tearDownAfterClass() throws Exception {
System.out.println("AfterClass 标注的方法 会最后执行");
}
@Test
public void test() {
System.out.println("test");
//路经比较特殊
BeanFactory factory = new ClassPathXmlApplicationContext("com/xx/spring/chap1/ioc.xml");
UserService service = (UserService) factory.getBean("service");
service.getUserDao().save();
}
@Test
public void test2() {
BeanFactory factory = new ClassPathXmlApplicationContext("com/xxx/spring/chap1/set.xml");
//User user = (User) factory.getBean("user");
//User user = (User) factory.getBean("user",User.class);
//User user = (User) factory.getBean(User.class); //只有唯一的bean的时候才使用这种方式
//System.out.println(user);
System.out.println(factory.getType("user")); //获取user实例的类型
User user = (User) factory.getBean("user");
User user2 = (User) factory.getBean("user");
System.out.println(user == user2);//true -- 单例 --这是可以控制的在配置文件中 bean scope="prototype"-->会变成原型模式 这时结果会是false
System.out.println(factory.isPrototype("user"));//是否为原型 false
System.out.println(factory.isSingleton("user"));//是否为单例 true
System.out.println(factory.isTypeMatch("user", User.class));//判断 user实例是否为这种类型 true
String[] str = factory.getAliases("user"); //获取别名
for(int i=0;i<str.length;i++){
System.out.println(str[i]);//user2
}
}
}
使用junit测试时候,注解@BeforeClass的会先于@Test注解的方法运行,@AfterClass最后运行,junit相关的jar最好使用4.4以上的版本
上边的案例factory.getBean("user",User.class);第一参数是set.xml文件中对应bean的name值或id值.
- System.out.println(user == user2);
System.out.println(user == user2);//true
上边返回true,说明默认的是单利模式,可以通过scope改变其范围为scope="prototype"变为原型模式,这样每次初始化bean对象的时候,都会返回一个新的。
4.2Bean容器的初始化
Bean容器的初始化
两个基础包:
org.springframework.beans
org.springframework.context
BeanFactory提供配置结构和基本功能,加载并初始化Bean
ApplicationContext保存了Bean对象并在spring中被广泛使用
集中常用的使用场景:
常用的文件初始化方式:
FileSystemXmlApplicationContext context = new FileSystemXmlApplicationContext("F:/workspace/appcontext.xml");
ApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap1/coll.xml");
BeanFactory factory = new ClassPathXmlApplicationContext("com/xxxspring/chap1/ioc.xml");
在webapp中的我们一般配置到web.xml文件中
1.
-
- <context-param>
- <param-name>contextConfigLocation</param-name>
- <param-value>classpath:action.xml,classpath:dao.xml,classpath:service.xml</param-value>
- </context-param>
-
- <listener>
- <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
- </listener>
<!-- 配置contextConfigLocation指定spring将要使用的配置文件 -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:action.xml,classpath:dao.xml,classpath:service.xml</param-value>
</context-param>
<!-- 配置listner让spring读取配置文件-->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
2.load-on-startup标签指定启动顺序,1为指在启动服务器的时候初始化容器
- <listener>
- <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
- </listener>
-
- lt;servlet>
- <servlet-name>remoting</servlet-name>
- <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
- <init-param>
- <param-name>contextConfigLocation</param-name>
- <param-value>classpath:spring-remoting-servlet.xml</param-value>
- </init-param>
- <load-on-startup>1</load-on-startup>
- </servlet>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>remoting</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-remoting-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
4.3Bean的两种注入方式
a.设置值注入
b.构造注入
设置值注入案例:
基本类型的注入: 通过<property name="属性名", value="属性值/">为对应类对象初始化的值,这种方式必须在类中为对应的属性提供getxxx,setxx方法
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
- <bean name="user,user2" class="com.xxx.spring.ioc.bean.User">
- <property name="id" value="1"/>
- <property name="name" value="tom"/>
- <property name="age" value="20"/>
- <property name="gender" value="male"/>
- </bean>
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean name="user,user2" class="com.xxx.spring.ioc.bean.User">
<property name="id" value="1"/>
<property name="name" value="tom"/>
<property name="age" value="20"/>
<property name="gender" value="male"/>
</bean>
</beans>
引用类型的注入:<property name="属性名" ref="引用的bean"></property>,被引入的bean和引入处可以不在同一个xml文件中,因为所有bean都会被
容器初始化并保存到容器中
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
- <bean name="memberService" class="com.xxx.run.service.impl.IMemberServiceImpl">
- <property name="memberDao" ref="memberDao"></property>
- </bean>
- <bean name="memberDao" class="com.xxx.run.dao.impl.IMemberDaoImpl">
- </bean>
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean name="memberService" class="com.xxx.run.service.impl.IMemberServiceImpl">
<property name="memberDao" ref="memberDao"></property>
</bean>
<bean name="memberDao" class="com.xxx.run.dao.impl.IMemberDaoImpl">
</bean>
</beans>
构造注入
顾名思义,使用构造器对对象的初始化注入对应的值,实现方式有如下3种
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
- <bean name="teacher" class="com.xxx.spring.ioc.bean.Teacher">
-
- <constructor-arg name="id" value="1"/>
- <constructor-arg name="name" value="tom"/>
- <constructor-arg name="gender" value="male"/>
-
- <!-- <constructor-arg index="0" value="2"/>
- <constructor-arg index="1" value="jack"/>
- <constructor-arg index="2" value="male"/> -->
-
- <!-- <constructor-arg type="int" value="3"/>
- <constructor-arg type="String" value="rose"/>
- <constructor-arg type="String" value="female"/> -->
- </bean>
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean name="teacher" class="com.xxx.spring.ioc.bean.Teacher">
<!-- 1.按照属性名赋值 ,调用有参数的构造器,顺序是参数顺序-->
<constructor-arg name="id" value="1"/> <!-- person(int id,String name, String gender) -->
<constructor-arg name="name" value="tom"/>
<constructor-arg name="gender" value="male"/>
<!-- 2.index从0开始,按照属性在构造器中出现的顺序赋值 索引值是构造器中的属性顺序 -->
<!-- <constructor-arg index="0" value="2"/>
<constructor-arg index="1" value="jack"/>
<constructor-arg index="2" value="male"/> -->
<!-- 3.按照类型进行赋值,如果出现相同的类型,按照属性在构造器中出现的顺序进行复制 -->
<!--
<constructor-arg type="int" value="3"/>
<constructor-arg type="String" value="rose"/>
<constructor-arg type="String" value="female"/> -->
</bean>
</beans>
Teacher.java
- public class Teacher implements Serializable{
- private static final long serialVersionUID = 1L;
- private int id;
- private String name;
- private String gender;
-
- public Teacher(int id, String name, String gender) {
- super();
- this.id = id;
- this.name = name;
- this.gender = gender;
- }
-
- @Override
- public String toString() {
- return "Teacher [id=" + id + ", name=" + name + ", gender=" + gender
- + "]";
- }
- }
public class Teacher implements Serializable{
private static final long serialVersionUID = 1L;
private int id;
private String name;
private String gender;
public Teacher(int id, String name, String gender) {
super();
this.id = id;
this.name = name;
this.gender = gender;
}
@Override
public String toString() {
return "Teacher [id=" + id + ", name=" + name + ", gender=" + gender
+ "]";
}
}
测试
- @Test
- public void test3() throws Exception {
- ApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap1/constructor.xml");
- Teacher teacher = (Teacher) ac.getBean("teacher");
- System.out.println(teacher);
- }
@Test
public void test3() throws Exception {
ApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap1/constructor.xml");
Teacher teacher = (Teacher) ac.getBean("teacher");
System.out.println(teacher);//Teacher [id=1, name=tom, gender=male]
}
5.Bean
下边我们来了解一下Bean的:
Bean的作用域
Bean的生命周期
Bean的自动装配
Resources和ResourceLoader
5.1Bean的生命周期
Spring中Bean的声明周期的创建和初始化都是由Spring管理创建的,如下Life实现BeanNameAware,BeanFacotryAware,可以获取到一些对应的资源
- import org.springframework.beans.BeansException;
- import org.springframework.beans.factory.BeanFactory;
- import org.springframework.beans.factory.BeanFactoryAware;
- import org.springframework.beans.factory.BeanNameAware;
-
- public class Life implements BeanNameAware,BeanFactoryAware{
- private String name;
-
- public Life(){
- System.out.println("调用无参构造器");
- }
-
- public String getName() {
- return name;
- }
-
- public void setName(String name) {
- System.out.println("调用setName方法");
- this.name = name;
- }
-
- public void myInit() {
- System.out.println("调用myInit方法");
- }
-
- public void myDestory(){
- System.out.println("调用myDestory方法");
- }
-
- @Override
- public void setBeanFactory(BeanFactory arg0) throws BeansException {
- System.out.println("调用setBeanFactory方法");
-
- }
-
- @Override
- public void setBeanName(String arg0) {
- System.out.println("调用setBeanName方法");
- }
- }
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanNameAware;
public class Life implements BeanNameAware,BeanFactoryAware{
private String name;
public Life(){//一加载就会调到用
System.out.println("调用无参构造器");
}
public String getName() {
return name;
}
public void setName(String name) {
System.out.println("调用setName方法");
this.name = name;
}
public void myInit() {
System.out.println("调用myInit方法");
}
public void myDestory(){
System.out.println("调用myDestory方法");
}
@Override
public void setBeanFactory(BeanFactory arg0) throws BeansException {
System.out.println("调用setBeanFactory方法");
}
@Override
public void setBeanName(String arg0) {
System.out.println("调用setBeanName方法");
}
}
life.xml文件配置
init-method指明bean初始化需要执行的方法,
destory-method指明bean销毁需要执行的方法
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xmlns:u="http://www.springframework.org/schema/util"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
- http://www.springframework.org/schema/util
- http://www.springframework.org/schema/util/spring-util-3.2.xsd">
-
- <bean name="life" class="com.xxx.spring.ioc.bean.Life" init-method="myInit" destroy-method="myDestory">
- <property name="name" value="tom"></property>
- </bean>
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:u="http://www.springframework.org/schema/util"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-3.2.xsd">
<!-- 调用set方法赋值后会调用myInit方法 myDestory方法最后调用-->
<bean name="life" class="com.xxx.spring.ioc.bean.Life" init-method="myInit" destroy-method="myDestory">
<property name="name" value="tom"></property>
</bean>
</beans>
测试:
注意:在xml文件中指明destory-method需要执行的方法后,bean生命周期并不会自动去掉用myDestory方法,需要ac.detstory(),才会调用
- @Test
- public void life(){
- ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap2/life.xml");
- Life life = ac.getBean("life",Life.class);
- System.out.println(life);
- ac.destroy();
- }
@Test
public void life(){//springBean的生命周期
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap2/life.xml");
Life life = ac.getBean("life",Life.class);
System.out.println(life);
ac.destroy();
}
结果:
调用无参构造器
调用setName方法
调用setBeanName方法
调用setBeanFactory方法
调用myInit方法
com.briup.spring.ioc.bean.Life@4f0b5b
调用myDestory方法
AfterClass 标注的方法 会最后执行
5.2Bean作用域
介绍两个常用的
scope="prototype"原型模式,该模式下每次都会创建一个新的对象
<bean id="user" class="com.briup.spring.ioc.bean.User" scope="prototype"></bean>
scope = "singleton" 单例模式,该模式下容器中只会存在一个这样的对象
<bean id="user" class="com.briup.spring.ioc.bean.User" scope="singleton"></bean>
其他的参考:
http://blog.csdn.net/fengruifang/article/details/6522262
5.3Bean的自动装配
上边的Bean不管通过设置值注入,或通过构造器注入,我们都显示的声明了需要注入的值
还有一种方式也比较常用,对应引用类型的注入我们可以通过autowire自动注入
autowire有三种方式
1.constructor
如下边我们不显示声明address属性的值,autowire=“constructor”,即初Student中提供了
public Student(Address address) {
this.address = address;
}
构造器,初始化Bean的时候,会去容器中查找Address.class对象是否存在,如果存在,则注入到该bean对象中,如存在address为null
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
- <bean name="student" class="com.xxx.spring.ioc.bean.Student" autowire="constructor">
- <property name="name" value="tom"/>
- <property name="age" value="20"/>
-
- </bean>
- <bean name="address" class="com.briup.spring.ioc.bean.Address">
- <property name="country" value="中国"></property>
- <property name="province" value="江苏"></property>
- <property name="city" value="苏州"></property>
- </bean>
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean name="student" class="com.xxx.spring.ioc.bean.Student" autowire="constructor"><!-- byName byType constructor(一定要提供一个单参数的构造器)-->
<property name="name" value="tom"/>
<property name="age" value="20"/>
<!--
<property name="address" ref="address"/> -->
</bean>
<bean name="address" class="com.briup.spring.ioc.bean.Address">
<property name="country" value="中国"></property>
<property name="province" value="江苏"></property>
<property name="city" value="苏州"></property>
</bean>
</beans>
2.byName
同理,autowire=“byName”,初始化bean的时候,会去容器中查找名字为address的bean注入到student对象中,Student需要提供对应的getxx,setxx
3.byType
autowire=“byType”,初始化bean的时候,会取容器中通过类型查找是否有Class为Address.class类型的对象,查找到则注入到student对象中需要提供getxx,setxx
5.3 Aware
spring中提供了许多已Aware结尾的类,这些类可以获取容器中的一些资源
比如ApplicationContextAware,可以获取applicationCcontext中的内容
BeanNameAware可以获取到Bean的beanName
aware.xml
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
- <bean name="applicationAawareTest" class="com.xxx.spring.aop.bean.AwareTest"></bean>
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean name="applicationAawareTest" class="com.xxx.spring.aop.bean.AwareTest"></bean>
</beans>
AwareTest.java
- import org.springframework.beans.BeansException;
- import org.springframework.beans.factory.BeanNameAware;
- import org.springframework.context.ApplicationContext;
- import org.springframework.context.ApplicationContextAware;
-
- public class AwareTest implements ApplicationContextAware,BeanNameAware{
-
- @Override
- public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
- System.out.println(applicationContext.getBean(AwareTest.class));
- }
-
- @Override
- public void setBeanName(String beanName) {
- System.out.println(beanName);
- }
-
- }
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
public class AwareTest implements ApplicationContextAware,BeanNameAware{
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
System.out.println(applicationContext.getBean(AwareTest.class));
}
@Override
public void setBeanName(String beanName) {
System.out.println(beanName);
}
}
测试:
- @Test
- public void AwareTest(){
- ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap1/aware.xml");
- AwareTest awareTest = ac.getBean("applicationAawareTest",AwareTest.class);
- System.out.println(awareTest);
- }
@Test
public void AwareTest(){
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap1/aware.xml");
AwareTest awareTest = ac.getBean("applicationAawareTest",AwareTest.class);
System.out.println(awareTest);
}
结果:
applicationAawareTest
com.xxx.spring.aop.bean.AwareTest@1d8fe20
com.xxx.spring.aop.bean.AwareTest@1d8fe20
5.4Resource统一文件资源接口
Resources针对文件的统一接口,用于操作本地资源或网络资源,或其他
-UrlResource:URL对应的资源,根据一个URL地址既可以构建
-ClassPathResource:获取类路径下的资源文件
-FileSystemResource:获取文件系统中的资源文件
-ServletContextResource:ServletContext封装资源,用于访问ServletContext环境下的资源
-InputStreamResource:针对输入流封装的资源
-ByteArrayResource:针对字节数组封装的资源
ResourceLoader
-所用的application context 实现了ResourceLoader接口
spring中ResourceLoader定义如下:
- public interface ResourceLoader{
- Resource getResource(String location);
- }
public interface ResourceLoader{
Resource getResource(String location);
}
getResource中location的写法有如下几种
prefix前缀
案例 说明
classpath:
classpath:com/briup/spring/chap2/life.xml 从classpath中加载
file: file:/data/life.xml用URL从文件系统中加载
http: http://myserver/logoo.png通过URL从网络加载
(none)
/spring/chap2/life.xml 这种相对路径的写法依赖于ApplicationContext
spring中的使用
Resource template = ctx.getResource("some/resource/path/myTemplate.txt");
Resource template = ctx.getResource("classpath:some/resource/path/myTemplate.txt");
Resource template = ctx.getResource("file:some/resource/path/myTemplate.txt");
案例:
resources.xml
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http://www.springframework.org/schema/beans
- http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
- <bean name="resourcetest" class="com.briup.spring.aop.bean.ResourceTest"/>
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.2.xsd">
<bean name="resourcetest" class="com.briup.spring.aop.bean.ResourceTest"/>
</beans>
ResourceTest.java
由于spring中所有的applicationcontext实现了ContextLoader接口, 所以我们实现applicationContext即有了ResourceLoader的能力
下边:classpath:在eclipse中会加载src下的config.txt文件
- import java.io.IOException;
-
- import org.springframework.beans.BeansException;
- import org.springframework.context.ApplicationContext;
- import org.springframework.context.ApplicationContextAware;
- import org.springframework.core.io.Resource;
-
-
-
- public class ResourceTest implements ApplicationContextAware{
-
- private ApplicationContext ApplicationContext;
-
- @Override
- public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
- this.ApplicationContext = applicationContext;
- }
-
- public void resource() throws IOException{
-
-
-
- Resource resource = ApplicationContext.getResource("url:http://repo.springsource.org/libs-release-local/org/springframework/spring/3.2.4.RELEASE/spring-framework-3.2.4.RELEASE-dist.zip");
- System.out.println(resource.getFilename());
- System.out.println(resource.contentLength());
- System.out.println(resource.getInputStream());
- }
- }
import java.io.IOException;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.core.io.Resource;
//所有的ApplicationContext实现了ResourceLoader接口
public class ResourceTest implements ApplicationContextAware{
private ApplicationContext ApplicationContext;
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.ApplicationContext = applicationContext;
}
public void resource() throws IOException{
//Resource resource = ApplicationContext.getResource("config.txt");//默认为classpath
//Resource resource = ApplicationContext.getResource("classpath:config.txt");
//Resource resource = ApplicationContext.getResource("file:D:\\workspace\\xnxy_spring\\src\\config.txt");
Resource resource = ApplicationContext.getResource("url:http://repo.springsource.org/libs-release-local/org/springframework/spring/3.2.4.RELEASE/spring-framework-3.2.4.RELEASE-dist.zip");
System.out.println(resource.getFilename());//获取文件名
System.out.println(resource.contentLength()); //获取文件长度
System.out.println(resource.getInputStream());//获取输入流
}
}
测试:
- @Test
- public void ResourceTest(){
- ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/briup/spring/chap1/resources.xml");
- ResourceTest resourceTest = ac.getBean("resourcetest",ResourceTest.class);
- try {
- resourceTest.resource();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
-
@Test
public void ResourceTest(){
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/briup/spring/chap1/resources.xml");
ResourceTest resourceTest = ac.getBean("resourcetest",ResourceTest.class);
try {
resourceTest.resource();
} catch (IOException e) {
e.printStackTrace();
}
}
6.Bean容器的注解实现
下边我们主要了解如下使用:
Classpath扫描与组件管理
类的自动检测与注册Bean
<context:annotation-config/>
@Component, @Repository, @Service, @Constroller
@Required
@Autowired
@Qualifier
@Resource
6.1classpath扫描与组件管理
从Spring3.0开始,Spring JavaConfig项目提供了很多特性,包括使用java而不是XML定义Bean,比如
@Configuration, @Bean, @Import, @DependsOn
@Component是Spring中的一个通用注解,可以用于任何Bean,相当于注解的超类,如果不知道位于那个层,一般使用该注解
@Repository, @Service, @Controller是更具有针对性的注解
- @Repository,通常用于注解DAO,即持久层的注解
- @Service,通常用于追注解Service类,即服务层
- @Controller通常用于注解Controller,即控制层(MVC)
6.2类的自动检测与注册Bean
我们再xml下配置如下标签,可以指定某个包路劲,扫描该包以及子包下,使用了spring注解的bean注册哦容器中,basp-package指向扫描那个包下的注解类
- <context:component-scan base-package="spring.aop.bean.annotation"></context:component-scan>
<context:component-scan base-package="spring.aop.bean.annotation"></context:component-scan>
我们还可以使用如下标签,context:annotation-config,不过context:component-scan包含context:annotation-config的全部功能,通常使用前者后,不再使用后者context:component-scan一般用于基于类的注解(包括成员变量或成员方法的注解),但是context:annotation-config只能在完成bean注册后,去处理bean类中的成员变量或成员方法的注解.
过虑注解:
<!--默认情况下,spring中自动发现并被注册bean的条件是:
使用@Component, @Repository, @Service, @Constroller其中之一的注解
或者使用基于@Component的自定义注解
可以通过过滤器修改上边的行为,如下边的例子XML配置忽略所有@Repository注解并用“stub”代替
-->
- <context:component-scan base-package="spring.aop.bean.annotation">
-
- <context:include-filter type="regex" expression=".*Stub.*Repository"/>
-
- <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Repository"/>
- </context:component-scan>
<context:component-scan base-package="spring.aop.bean.annotation">
<!-- -->
<context:include-filter type="regex" expression=".*Stub.*Repository"/>
<!-- 排除@Repository注解 -->
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Repository"/>
</context:component-scan>
6.3使用注解管理bean
这里我们先使用 @Bean @Service @Repository @Componet
扫描过程中组件自动检测,那么Bean名称是有BeanNameGenerator生成的( @Component, @Repository, @Service, @Controller
都会有个name属性用于显示设置BeanName)
Service
//显示设置beanName,相当于在xml配置bean的是id的值
@Service("myMoveLister")
public class simpleLlister{
//..
}
Dao
//设置beanName默认使用类名,首字母小写作为beanName
@Repository
public class MovieFinderImpl implements MovieFinder{
}
6.3.1 作用域scope
作用域的注解Scope
通常情况下自动查找的Spring组件,其Scope是singleton,其Spring2.5提供了Scope的注解 @Scope
@Scope("prototype") //括号中指定Scope的范围,默认
@Repository
public class MovieFinderImpl implements MovieFinder{
}
也可以自定义scope策略,实现ScopeMetadataResolver接口并提供一无参数的构造器
<context:component-scan base-package="spring.aop.bean.MyScopeResolver"></context:component-scan>
6.3.2注解的具体案例使用
//由于不知道其作用于DAO或Service所以使用通用注解,如果知道具体作用在那层,我们一班使用更具体注解方式如@Service,@Repository等
-
- @Scope("prototype")
- @Component("beanAnnotation")
- public class BeanAnnotation {
-
- public void say(String arg){
- System.out.println("BeanAnnotation: "+arg);
- }
- }
//@Component -->默认使用类名小写作为bean的name
@Scope("prototype") //括号中为Scope的范围,这里设置为原型模式
@Component("beanAnnotation")
public class BeanAnnotation {
public void say(String arg){
System.out.println("BeanAnnotation: "+arg);
}
}
测试:
- @Test
- public void testAnnotation(){
- ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap4/annotation.xml");
-
- BeanAnnotation beanAnnotation1 = ac.getBean("beanAnnotation",BeanAnnotation.class);
- BeanAnnotation beanAnnotation2 = ac.getBean("beanAnnotation",BeanAnnotation.class);
- System.out.println(beanAnnotation1);
- System.out.println(beanAnnotation2);
-
-
-
- }
@Test
public void testAnnotation(){
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap4/annotation.xml");
//@Component没有value值的话,默认使用类名首字母小写作为bean的id,指定value以value值为准作为id
BeanAnnotation beanAnnotation1 = ac.getBean("beanAnnotation",BeanAnnotation.class);
BeanAnnotation beanAnnotation2 = ac.getBean("beanAnnotation",BeanAnnotation.class);
System.out.println(beanAnnotation1);
System.out.println(beanAnnotation2);
//结果
//com.xxx.spring.aop.bean.annotation.BeanAnnotation@1598d5f
//com.xxx.spring.aop.bean.annotation.BeanAnnotation@505fd8
}
6.3.3一个不常用的注解@Required
@Required注解使用于注解bean属性的setter方法
这个注解仅仅标识,受影响的bean属性必须在配置时被填充,通过bean定义或通过自动装配一个明确的属性值
这个注解并不是很常用,更常用的是@Autowired
pulic class simpleMovieLister{
private MoiveFinder movieFinder;
@Required
public void setMovieFinder(MovieFinder movieFinder){
this.movieFinder = movieFinder;
}
//..
}
6.3.4@Autowired
这个注解相当于我们之前在xml文件中配置的autowire="constructor/byName/byType",只不过我们这里使用@Autowired方式注解方式,且默认是通过类型判断,意思就是不使用byName,和construtor。通过@Autowired注解,spring会自动去容器中查找对应的类型,注入到该属性中,且bean类中,使用@Autowired注解其属性,我们可以不用提供getter,setter方法
使用@Autowired
@Autowried对属性进行注解的时候,我们可以省略getter,setter方法,通过对应的bean的类型,对属性值注入
@Autowried对seter方法进行注解的时候,可以注入对应的值
@Autowried对构造器进行注解的时候,可以通过类型找到对应的bean注入
@Autowried可以将 @Autowried为”传统“的setter方法代替 @Required
@Autowried自动注入,会去容器中按照类型查找对应的bean注入
案例:
setter中使用
- pulic class simpleMovieLister{
-
- private MoiveFinder movieFinder;
-
- @Autowried
- public void setMovieFinder(MovieFinder movieFinder){
- this.movieFinder = movieFinder;
- }
-
- }
pulic class simpleMovieLister{
private MoiveFinder movieFinder;
@Autowried
public void setMovieFinder(MovieFinder movieFinder){
this.movieFinder = movieFinder;
}
//..
}
属性和构造器中使用
- pulic class MovieRreCommender{
-
- 成员变量中
- @Autowried
- private MovieCatalog movieCatalog;
-
- private CustomerPreferenceDao customerPreferenceDao;
-
-
- @Autowried
- public MovieRreCommender(CustomerPreferenceDao customerPreferenceDao){
- this.CustomerPreferenceDao = CustomerPreferenceDao;
- }
- }
pulic class MovieRreCommender{
成员变量中
@Autowried
private MovieCatalog movieCatalog;
private CustomerPreferenceDao customerPreferenceDao;
//构造器中
@Autowried
public MovieRreCommender(CustomerPreferenceDao customerPreferenceDao){
this.CustomerPreferenceDao = CustomerPreferenceDao;
}
}
上边的seter方式,构造器方式,属性方式,效果都是一样的,使用其中任何一种,都可以实现注入。不过由于,@Autowired是通过类型判断是否注入到使用该注解地方,假如容器中出现两个以上的相同类型的bean实例,就会报错,这时我们就必须指定注入那个id名的bean实例,主要有两种方法解决该问题:
@Autowired(requried=false), @Qualifie("beanName)指定@Autowired注入那个bean实例
6.3.5@Autowried(requried=false)
默认情况下,如果因找不到合适的bean将会导致autowiring失败抛出异常,可以通过下边
这种方式避免
pulic class simpleMovieLister{
private MoiveFinder movieFinder;
@Autowried(requried=false)//指明该属性不是必须的,找不到的情况下不会抛出异常
public void setMovieFinder(MovieFinder movieFinder){
this.movieFinder = movieFinder;
}
//..
}
提示:每一类中只能有一个构造器被标记为requried=ture建议将 @Autowired的必要属性时,使用 @Requried注解
6.3.6@Qualifier--配合 @Autowired
如果使用 @Autowired自动装配可能存在多个相同类型的bean的时候,可以使用spring的 @Qualifier
注解缩小注解范围(或指定唯一),也可以用于指定单独的构造参数的方法参数
可以适用于注解集合类型的变量
案例:
- public class MovieRecommander{
- @Autowired
- @Qualifier("beanName")
- private MovieCatalog movieCatalog;
-
- private CustomerPreferenceDao customerPreferenceDao;
- <span style="white-space:pre"> </span>
- public void prepare(@Qualifier("beanName")CustomerPreferenceDao customerPreferenceDao){
- this.customerPreferenceDao = customerPreferenceDao;
- }
- }
public class MovieRecommander{
@Autowired
@Qualifier("beanName")
private MovieCatalog movieCatalog;
private CustomerPreferenceDao customerPreferenceDao;
<span style="white-space:pre">
</span>//@Qualifier也可以实现参数的注入
public void prepare(@Qualifier("beanName")CustomerPreferenceDao customerPreferenceDao){
this.customerPreferenceDao = customerPreferenceDao;
}
}
上边的案例:假设MovieCatalog在容器中存在多个相同的类型的情况下,可以结合使用 @Qualifier("beanName")
指定一个bean的id注入到该属性中,可以在方法的参数中使用
6.3.7@Autowired注解可以方便的注解那些众所周知的解析依赖性接口
比如说:BeanFacotry,ApplicationContext,Environment,ResourceLoader,ApplicaiontEventPublisher, MessageSource等
- pulic class simpleMovieLister{
-
- @Autowired
- private AplicationContext context;
-
- public simpleMovieLister(){}
-
- }
pulic class simpleMovieLister{
@Autowired
private AplicationContext context;
public simpleMovieLister(){}
}
上边的案例使用autowired注解ApplicationContext,这样我们就可以活ApplicatioinContext容器总的bean对象
6.3.8@Autowired将容器中相关类型的bean注入到一个集合或数组中
使用@Autowired注解,可以将容器中的bean实例注入到集合或数组中,如果是注入到数组中通过配合@Order("排序值"),可以实现对数组或list的排序,也只能对数组或list排序,其他的如Map是不需要排序的。
案例:接口BeanInfterface
- public interface BeanInterface {
-
-
- }
public interface BeanInterface {
}
实现类1:
- @Order(1)
- @Component
- public class BeanImplOne implements BeanInterface {
-
- }
@Order(1)
@Component
public class BeanImplOne implements BeanInterface {
}
实现类2:
- @Order(2)
- @Component
- public class BeanImplTwo implements BeanInterface {
-
- }
@Order(2) //Order排序注解只对list,或数组集合有效括号里边是排序顺序
@Component
public class BeanImplTwo implements BeanInterface {
}
调用类:
- import java.util.List;
- import java.util.Map;
- import java.util.Map.Entry;
- import java.util.Set;
- import org.springframework.beans.factory.annotation.Autowired;
- import org.springframework.stereotype.Component;
-
- @Component
- public class BeanInvoker {
-
- @Autowired
-
- private List<BeanInterface> list;
-
-
-
- @Autowired
- private Map<String, BeanInterface> map;
-
- public void print(){
- if(list != null && 0 != list.size()){
- System.out.println("list...");
- for(BeanInterface beanInterface:list){
- System.out.println(beanInterface.getClass().getName());
- }
- }
- if(map != null && 0 != map.size()){
- System.out.println("map...");
- Set<Entry<String, BeanInterface>> entrySet = map.entrySet();
- for(Entry<String, BeanInterface> entry: entrySet){
- System.out.println(entry.getKey()+"--"+entry.getValue().getClass().getName());
- }
- }
- }
- }
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component
public class BeanInvoker {
@Autowired //该注解会将所有的BeanInterface类型的bean注入到该list中
//如果bean有 @Order注解可以实现排序
private List<BeanInterface> list;
//该注解会将所有的BeanInterface类型的bean注入到该map中,key值为bean的名字
//是String类型,map类型无排序可言
@Autowired
private Map<String, BeanInterface> map;
public void print(){
if(list != null && 0 != list.size()){
System.out.println("list...");
for(BeanInterface beanInterface:list){
System.out.println(beanInterface.getClass().getName());
}
}
if(map != null && 0 != map.size()){
System.out.println("map...");
Set<Entry<String, BeanInterface>> entrySet = map.entrySet();
for(Entry<String, BeanInterface> entry: entrySet){
System.out.println(entry.getKey()+"--"+entry.getValue().getClass().getName());
}
}
}
}
测试类:
- @Test
- public void testAutowired2(){
- ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap4/annotation.xml");
- BeanInvoker beanInvoker = (BeanInvoker) ac.getBean("beanInvoker");
- beanInvoker.print();
- }
@Test
public void testAutowired2(){
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap4/annotation.xml");
BeanInvoker beanInvoker = (BeanInvoker) ac.getBean("beanInvoker");
beanInvoker.print();
}
结果:
list...
com.xxx.spring.aop.bean.annotation.BeanImplOne
com.xxx.spring.aop.bean.annotation.BeanImplTwo
map...
beanImplOne--com.xxx.spring.aop.bean.annotation.BeanImplOne
beanImplTwo--com.xxx.spring.aop.bean.annotation.BeanImplTwo
6.4@Bean注解的使用
@Bean是基于容器的注解,我们可以在使用@Compent注解的地方配合@Bean使用,不过@Bean注解一般不于@Compent注解使用,我们一般使用
@Bean注解配合@Configuration注解使用,相当于我们再xml配置文件中定义了<bean></bean>
使用:
- @Configuration
- public class Appconfig{
-
- @Bean("myservice")
- public Myservice myservice(){
- return new MyServiceImpl();
- }
-
-
-
-
- }
@Configuration //相当于配置文件
public class Appconfig{
@Bean("myservice")//假如bean的name属性没有指定名字的话,注入的是id为方法名的bean,一般我们指定name属性不容易出错
public Myservice myservice(){
return new MyServiceImpl();
}
/*
对比基于XML文件中的配置效果类似
<bean id="myservice" class="com.xxx.service.MyserviceImpl"></bean>
*/
}
@Bean中的其他他几个属性
之前我们再配置文件中使用过如下的配置,指定bean的初始化调时会执行的方法,和销毁会执行的方法
- <bean name="life" class="com.briup.spring.ioc.bean.Life" init-method="myInit" destroy-method="myDestory">
- <property name="name" value="tom"></property>
- </bean>
<bean name="life" class="com.briup.spring.ioc.bean.Life" init-method="myInit" destroy-method="myDestory">
<property name="name" value="tom"></property>
</bean>
我们使@Bean配置也可以实现上边这种效果
- public class Foo{
- public void init(){
-
- }
- }
-
- public class Bar{
- public void cleanup(){
-
- }
- }
public class Foo{
public void init(){
}
}
public class Bar{
public void cleanup(){
}
}
- @Configuration
- public class Appconfig{
-
- @Bean(name="life")
- public Life life(){
- return new Life();
- }
-
- @Bean(initMethod="init")
- public Foo foo(){
- return new Foo();
- }
-
- @Bean(destoryMethod=“cleanup”)
- public Bar bar(){
- return new Bar();
- }
- }
@Configuration
public class Appconfig{
@Bean(name="life") //定义bean的name
public Life life(){
return new Life();
}
@Bean(initMethod="init") //在初始化Foo的时候,会调用Foo.java中的init方法
public Foo foo(){
return new Foo();
}
@Bean(destoryMethod=“cleanup”) //在销毁Bar的时候会调用Bar.java中的cleanup中的方法
public Bar bar(){
return new Bar();
}
}
6.5使用注解模拟连接数据库
db.properties内容如下:
jdbc.driver=oracle.jdbc.driver.OracleDriver
jdbc.url=jdbc:oracle:thin:@localhost:1521:XE
jdbc.username=caojx
jdbc.password=caojx
config.xml配置如下
- <?xml version="1.0" encoding="UTF-8"?>
- <beans xmlns="http://www.springframework.org/schema/beans"
- xmlns:context="http://www.springframework.org/schema/context"
- xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
- xsi:schemaLocation="http:
- http:
- http:
- http:
- <!-- 加载db.properties文件 -->
- <context:property-placeholder location="classpath:db.properties"/>
- <!--context:component-scan包含context:annotation-config的全部功能,通常使用前者后,不再使用后者
- <context:component-scan base-package="com.briup.spring.aop.bean.annotation"></context:component-scan>
-
- </beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd" >
<!-- 加载db.properties文件 -->
<context:property-placeholder location="classpath:db.properties"/>
<!--context:component-scan包含context:annotation-config的全部功能,通常使用前者后,不再使用后者
<context:component-scan base-package="com.briup.spring.aop.bean.annotation"></context:component-scan>
</beans>
使用如下类,打印出配置文件中db.properties中的信息
- public class MyDriverManager {
-
- public MyDriverManager(String url, String userName, String password){
- System.out.println("url :"+url);
- System.out.println("userName :"+userName);
- System.out.println("password :"+password);
- }
-
- }
public class MyDriverManager {
public MyDriverManager(String url, String userName, String password){
System.out.println("url :"+url);
System.out.println("userName :"+userName);
System.out.println("password :"+password);
}
}
读取配置文件中的信息
- @Configuration
- @ImportResource("classpath:com/xxx/spring/chap4/config.xml")
- public class MyConnection {
-
-
- @Value("${jdbc.url}")
- private String url;
-
- @Value("${jdbc.username}")
- private String userName;
-
- @Value("${jdbc.password}")
- private String password;
-
- @Bean(name="myDriverManager")
-
- public MyDriverManager MyDriverManager(){
- return new MyDriverManager(url,userName,password);
- }
-
- }
@Configuration
@ImportResource("classpath:com/xxx/spring/chap4/config.xml") //指定配置文件的路径
public class MyConnection {
@Value("${jdbc.url}") //基本类型的变量使用@Value注解(括号里边是注入的值) ,这是使用${是读取配db.properties中的值}
private String url;
@Value("${jdbc.username}") //如果db.properties中写法为username默认取的是当前操作系统用户的名称,可以在db.properties定义username的时候使用jdbc.username
private String userName;
@Value("${jdbc.password}")
private String password;
@Bean(name="myDriverManager")
public MyDriverManager MyDriverManager(){
return new MyDriverManager(url,userName,password);
}
}
测试:
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/xxx/spring/chap4/annotation.xml");
System.out.println(ac.getBean("myDriverManager"));
结果:
url :jdbc:oracle:thin:@localhost:1521:XE
userName :caojx
password :caojx
com.briup.spring.aop.bean.annotation.MyDriverManager@152b54b
同时:@Bean注解也可以配置@Scope使用
- @Bean(name="myDriverManager")
- @Scope("prototype")
- public MyDriverManager MyDriverManager(){
- return new MyDriverManager(url,userName,password);
- }
-
- @Bean(name="myDriverManager")
- @Scope("singleton")
- public MyDriverManager MyDriverManager(){
- return new MyDriverManager(url,userName,password);
- }
@Bean(name="myDriverManager")
@Scope("prototype")
public MyDriverManager MyDriverManager(){
return new MyDriverManager(url,userName,password);
}
@Bean(name="myDriverManager")
@Scope("singleton")
public MyDriverManager MyDriverManager(){
return new MyDriverManager(url,userName,password);
}
提示:spring配置数据库连接,或事务管理这一块,将会专门使用一篇来说明。
6.6Spring对JSR的注解支持
JSR常见的注解有如下
@Resource等效于@Autowired与@Inject
@PostConstrct 初始化回掉
@PreDetory 销毁回调用
@Inject 等效于 @Autowired
@Named 与 @Compenet等效
6.6.1@Resource
@Resource的作用相当于@Autowired,只不过@Autowired按byType自动注入,
而@Resource默认按 byName自动注入罢了。
@Resource有两个属性是比较重要的,分是name和type,
Spring将@Resource注解的name属性解析为bean的名字,而type属性则解析为bean的类型。
所以如果使用name属性,则使用byName的自动注入策略,而使用type属性时则使用byType自动注入策略。如果既不指定name也不指定type属性,这时将通过反射机制使用byName自动注入策略。
@Resource装配顺序
1. 如果同时指定了name和type,则从Spring上下文中找到唯一匹配的bean进行装配,找不到则抛出异常
2. 如果指定了name,则从上下文中查找名称(id)匹配的bean进行装配,找不到则抛出异常
3. 如果指定了type,则从上下文中找到类型匹配的唯一bean进行装配,找不到或者找到多个,都会抛出异常
4. 如果既没有指定name,又没有指定type,则自动按照byName方式进行装配;如果没有匹配,则回退为一个原始类型进行匹配,如果匹配则自动装配;
5. 如果 @Resource用于方法中,默认使用方法名作为beanName,指定名字则使用名字
案例:
DAO
- import org.springframework.stereotype.Repository;
-
- @Repository
- public class JsrDAO {
-
- public void save(){
- System.out.println("JsrDao invoker");
- }
-
- }
import org.springframework.stereotype.Repository;
@Repository
public class JsrDAO {
public void save(){
System.out.println("JsrDao invoker");
}
}
Service
- import javax.annotation.PostConstruct;
- import javax.annotation.PreDestroy;
- import javax.annotation.Resource;
-
- import org.springframework.stereotype.Service;
-
- import com.briup.spring.aop.bean.annotation.dao.JsrDAO;
-
- @Service
- public class JsrService {
-
- @Resource
- private JsrDAO jsrDAO;
-
- @Resource
- public void setJsrDAO(JsrDAO jsrDAO){
- this.jsrDAO = jsrDAO;
- }
-
- public void save(){
- jsrDAO.save();
- }
-
- @PostConstruct
- public void init(){
- System.out.println("jsr Service init");
- }
-
- @PreDestroy
- public void destory(){
- System.out.println("jsr Service destory");
- }
-
- }
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import javax.annotation.Resource;
import org.springframework.stereotype.Service;
import com.briup.spring.aop.bean.annotation.dao.JsrDAO;
@Service
public class JsrService {
@Resource
private JsrDAO jsrDAO;
@Resource //作用与上边一样,二选一都可以
public void setJsrDAO(JsrDAO jsrDAO){
this.jsrDAO = jsrDAO;
}
public void save(){
jsrDAO.save();
}
@PostConstruct
public void init(){
System.out.println("jsr Service init");
}
@PreDestroy
public void destory(){
System.out.println("jsr Service destory");
}
}
提示:
@Resource的处理是由ApplicationContext中的CommonAnnotationBeanPostProecssor发现并处理的
CommonAnnotationBeanPostProecssor不仅支持 @Resource注解,还支持 @PostConstruct初始回调
和 @PreDestory销毁回调,前提是CommonAnnotationBeanPostProecssor是在ApplicationContext中注册的
测试结果:
@Test
public void testJsr(){
ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("com/briup/spring/chap4/annotation.xml");
System.out.println(ac.getBean("jsrService"));
ac.destroy();
}
结果:
jsr Service init
com.briup.spring.aop.bean.annotation.service.JsrService@7dc4cb
jsr Service destory
@Resource是一个比比较常用的JSR注解,对于JSR中的其他注解,这里不进行详细的介绍。